Grate structure



June 12, 1934.

E. E. JONES 1,962,958 GRATE STRUCTURE Filed July 19. 19:52 Z 29 li'fhraimlhion s Patented June 12, 1934 UNITED STATES PATENT OFFICE 8 Claims.

My invention relates to a grate structure designed primarily for use in burning semi-coking slack coal in furnaces, but it is to be understood that a grate structure, in accordance with my invention may be employed in any connection for which it may be found applicable.

The essential objects of my invention are to provide a grate structure for economically burning of semi-coking slack coal; burning cheap fuel with a minimum attention and secure a good overall efficiency; increasing the efficiency of combustion of the fuel; directing a larger portion of the products of combustion to the fire bowl surrounding the furnace thereby obtaining a better recovery of the heat units of the fuel into the heating system; maintaining a thicker fuel bed resulting in a longer period between firing; building the fuel bed into a high pyramid thereby making the central portion of the bed less active whereby as the volatile content of the fuel yields slowly, better recovery of the heat units of the fuel is obtained; obtaining coking of the fuel bed at its center by exclusion of air from such portion of the fuel bed, consequently less loss of carbon in the ash pit; the accumulation of a larger quantity of ash on the grate without shutting off draft to the fuel bed; the consuming of the fuel bed from the outside first, with the resultant ashes sealing the free passage of air at the outside portion of the fuel bed, whereby efficient combustion continues until practically all of the fuel is consumed; slowly yielding the volatile content of the fuel bed resulting in less smoke; maintaining a clean fire with minimum loss of combustible; and to attain these ends in a comparatively simple, strong, durable, compact, readily repaired, thoroughly efficient, and comparatively inexpensive structure.

A further object of the invention is to provide, in a manner as hereinafter set forth, a grate structure including an auxiliary grate element having as a part thereof a protecting means therefor acting to increase the efliciency of the combustion of the fuel, and with such means capable of being renewed at a small cost.

To the above ends essentially, and to others which may hereinafter appear, my invention consists of such parts and such combination of parts which fall within the scope of the invention as claimed.

In the drawing:

Figure 1 is an elevation of a grate structure in accordance with my invention.

Figure 2 is an inverted plan of the auxiliary grate element.

Figure 3 is a vertical sectional view of the auxiliary grate element.

The invention resides primarily in the construction of an auxiliary grate which is adapted to be arranged in superposed spaced relation with respect to an oscillatory main grate. The auxiliary grate can be installed in old and new furnaces of varying types by employing spacers of different thickness.

The drawing illustrates by way of example, one form of an oscillatory main shaking grate 1 to show the adaptation therewith, within a furnace, of the auxiliary grate 2 in superposed relation. A shaking lever 3 is attached to grate l, and the latter is of greater diameter than that of grate 2. The grate l axially thereof is formed with an opening 4 for the passage of a bolt 5 for connecting grate 2 with a coupling means 6 attached to the inner end of a shaking lever '7.

The auxiliary grate 2 is formed of two superimposed sections 8, 9 the former being hollow to provide a chamber and is constructed of metal. The section 9 is solid and formed from any suitable plastic composition used in the production of tiles, such as fire clay, or other refractory mac terial. The section 9 extends into the top and is flush with the outer side face of section 8. The section 9 is of dome-shape cross section, The section 9 acts as a protector for the top of section 8.

The section 8 will hereinafter be termed a body 5 part, and the section 9 a protector. The body part and protector are of circular form. The body part is chambered.

The body part includes a tapered or conically shaped annulus 10 having spaced vertically disposed inverted U-shaped cutouts 11 providing for the free passage of air into and below the fuel bed, the air moving in a horizontal direction in the form of jets or nozzle effect, especially as the ash accumulates on the main grate 1. The cutouts open at the bottom edge of the annulus 10 and provide relatively large unobstructed ports. Integral with the outer face of annulus 10 is a series of spaced outwardly directed radially disposed lugs 12 of arcuate contour in transverse cross section and substantially of quadrangular contour in lengthwise section. The lower faces of the lugs 12 are flush with the bottom edge 13 of annuhis 10. Each lug 12 is arranged between a pair of cutouts 11 and spaced equi-distant from the cutouts between which it is arranged. The top edge of annulus 10 is indicated at 14.

The body part includes a top formed of a flat central circular portion 15, an outwardly directed tapered or conically shaped intermediate portion 16 which depends from and has its smaller or upper end merging into the portion 15, and a flat circular outer portion 1? surrounding and integral with the bottom of portion 16. The outer portion 1'7 merges into the annulus below the top edge 14 of the latter whereby what may be termed vertically disposed annular flange 18 is provided which encompasses in spaced relation the lower part of portion 16. The flange 18, lower part of portion 15 and portion 17 provides a pocket or socket l8.

Depending from the lower face, conforming in cont-om to and of greater thickness than that of the central portion 15 is an abutment 19 formed with a vertical socket 20 of square contour opening at the bottom thereof.

Formed integral with the inner face of annulus l0 and the lower face of top portion 17 are spaced, vertical, inwardly extending, radially disposed reinforcing lugs 21. Each lug is arranged centrally between a pair of cutouts 11 and has its bottom edge inclining upwardly from the bottom edge 13 of annulus 10. Formed integral with the lower face of top portions 16 and 17, the inner face of annulus l1 and with the outer periphery of abutment 19 is a series of spaced, radially disposed depending ribs 22 of tapered cross section. The ribs have their bottom edges of curved contour throughout. The outer ends of the ribs correspond in height to the distance between top portion 17 and bottom edge 13 of annulus 10. The distance between the bottom edges of th ribs and bottom of said body part gradually increases from the outer to the inner ends of the ribs. The libs have their outer ends positioned at the center of the tops of th cutouts 11. The ribs are alternately disposed with respect to the lugs 21.

Ihe protector includes an outer portion 23 of the desired height and of dome-shape contour. The portion 23 is formed with a recess 24 to receive top portion 15 and the major part of top portion 16. The protector also includes an annular extension 25 on the bottom of portion 23. The inner side edge of extension 25 forms a continuation of the wall of recess 24. The outer side edge of extension 25 is spaced inwardly with respect to the outer face of portion 23. That part of the bottom of portion 23 arranged ou wardly of the extension 25 is indicated at 26. When section 9 which is the protector is mounted in superimposed relation with respect to section 8, the bottom part 26 of section 9 seats on edge 14 of section 2, extension 25 of section 9 is positioned into and snugly fits the walls of socket 18' of section 2 and socket 24 of section 9 receives the top portions 15 and 16 of section 2.

A spacer 27 of any suitable height is interposed between grates 1 and 2 for maintaining them in spaced relation. The spacer 27 corresponds in contour to and is positioned against the lower face of abutment 19. Spacer 27 has an axial opening 28. The spacer 27 can be formed of any suitable material.

The head 29 of the connecting and is to be seated in the socket 2c of abutment 19 to provide for a shaking action of grate 2 when lever '7 is operated. The shank of bolt 5 extends down through openings 28 and 4 and depends a suitable distance below grate 1.

The coupling means 6 comprises a sleeve 29 which is fixed on the inner end of lever '7. Integral with sleeve 29 is a clamping member 30 formed with a vertical opening 31 and a laterally disposed opening 82 arran ed at one side of and commiuiicating with opening 31. The wall of bolt 5 is square opening 32 is threaded. Engaging with the threaded wall of opening 32 is a clamping screw 33. The shank of bolt 5 is extended through opening 31 and member 30 and screw 33 coact to clamp bolt 5 to means 6.

The function of the lugs 12 on the outer face of the auxiliary grate is to break up and make the fuel bed porous, also to keep the main grate clean of ashes at this point, where most of the ashes originate.

The purpose of the ribs 22 underneath the auxiliary grate is first to provide structural strength; second to provide additional cooling surface; third made staggered in relation to lugs 21 so as to minimize the warping effects of alternate heating and cooling of auxiliary grate and fourth made to clear the main grate with proper clearance so as to keep the main grate surface entirely clear of accumulated ash underneath auxiliary grate.

The arrangement provides that the fuel bed is consumed from the outside first, the resultant ashes sealing the free passage of air at the outside portion of fuel bed, efficient combustion continues until practically all the fuel is consumed.

The only part of the auxiliary grate that is perishable is the protector which can be renewed at small cost, and the presence thereof not only protects the body part of the auxiliary grate from the destructive effects of the fuel bed but increases the efficiency of combustion of the fuel. The arrangement further provides for the central portion of the fuel bed to be less active and can be built into a high pyramid. A larger quantity of ash may accumulate on the grate without shutting off draft from the fuel bed, due to the vertical large openings provided by the cutouts in the body part of the auxiliary grate. Further with respect to the cutouts 11 it is evident that the greater the vertical height thereof the longer the fire can be carried before the accumulated cuts out the draft. In practice it has been found that the best results are obtained by allow ing ash to accumulate on the main grate 1 com pelling the major portion of the air entering the fuel bed to pass through cutouts 11. The air when passing horizontally through annulus 10 is highly pre-heated and must change its direction of travel from horizontal to vertical thereby producing high turbulence in the bed resulting in a more complete combustion. The cutouts 11 are open at their bottoms so as to present no obstruction to the discharge of the ashes. The cutouts 11 as shown gradually increase in width from their upper to their lower ends to prevent the ashes wedging therein. The cutouts 11 also provide for the expansion and contraction of each section of annulus 10 between them.

What I claim is:-

I. An auxiliary grate comprising, a unit consisting of a chambered body part formed of a closed top, an open bottom and with cutouts in its side. a protector positioned in superimposed relation with respect to and flush with the outer face of said body part, said protector being solid throughout of dome-shaped contour, and said body part being formed with integral radially disposed lugs on the outer face of its side between said cutouts and internally arranged alternately disposed radially extending reinforcing ribs and lugs integral with the inner face of its top, said reinforcing lugs arranged between the outer end portion of said ribs and the outer ends of the latter disposed centrally with respect to said cutouts.

2. An auxiliary grate comprising a unit consisting of a chambered metallic body part open at its bottom, closed at its top and having spaced cutouts in its sides, the outer face of the top of the unit being formed with an endless flange providing a pocket, a protector arranged in superimposed relation with respect to said body part and seated on said flange and extended into said pocket, said protector being formed of fire clay, solid throughout and of dome-shape cross section, said body part and protector being of circular contour and flush with each other, and said body part having its side provided with external radially disposed integral lugs flush with its bottom and arranged between said cutouts.

3. An auxiliary grate comprising a unit consisting of a chambered metallic body part open at its bottom, closed at its top and having spaced cutouts in its sides, the outer face of the top of the unit being formed with an endless flange providing a pocket, a protector arranged in superimposed relation with respect to said body part and seated on said flange and extended into said pocket, said protector being formed of fire clay, solid throughout and of dome-shape cross section, said body part and protector being of circular contour and flush with each other, said body part having its side provided with external radially disposed integral lugs flush with its bottom and arranged between said cutouts, and said body part having internal alternately arranged. radially disposed reinforcing ribs and lugs and an internal socket forming means between the inner ends of the ribs for connecting a shaking means therewith.

4. An auxiliary grate comprising a body provided with a chamber having a side and a top wall, said side wall being formed with spaced cutouts opening at the bottom of said body, said side wall being formed on its inner face with inwardly directed lugs and on its outer face with outwardly directed lugs, said top wall being formed with depending socket forming means for receiving a shaker element and with radially disposed ribs extending from said means and having their outer ends opposing said cutouts.

5. An auxiliary grate comprising a unit providing a circular chamber open throughout its bottom, the side wall of said chamber being formed with vertical openings gradually increasing in width downwardly and with lugs between said openings, the top wall of said chamber being formed centrally with a depending socket forming means for the reception of a shaker element and with ribs extending from said means to said side wall, the ribs being alternately disposed with respect to said lugs, and said lugs being alternately disposed with respect to said openings.

6. An auxiliary grate comprising a unit providing a chamber open throughout its bottom, the side wall of said chamber being formed with vertical cutouts opening at the bottom thereof and with lugs on its inner and outer faces flush with its bottom, the outer lugs being of less height than and aligning with the inner lugs, the outer lugs being arranged between and of less height than said cutouts, and the top wall of said chamber being formed with depending radially disposed ribs alternately disposed with respect to said inner lugs.

'7. An auxiliary grate comprising an upper and a lower section arranged in superimposed relation, said upper section formed of a solid body of fire resisting material having its lower face provided centrally with a recess and with a depending annular extension spaced from the outer face of said body the inner edge of said extension forming a downward continuation of the wall of the recess, said lower section consisting of an intermediate conically shaped body open at its lower end, a flat top for said body and an outer and upwardly extended part adjacent the lower edge of said body, said body being provided with spaced cutouts opening at its lower edge, said top formed of a flat circular upper part having its outer edge merging into the inner face of said body below the upper edge of the latter and corresponding in contour to the shape of said recess, the base of said recess seated upon said flat top, the wall of the recess seated against said intermediate part, the depending extension being seated upon the portion of said outer extended part adjacent said intermediate part, and that outer portion of the lower face of the upper section adjacent said extension seated upon the upper outer edge of said extended part, and said flat top having depending therefrom a socket forming means for receiving a shaker element.

8. An auxiliary grate as defined in claim 7 having its inner face formed with radially disposed ribs, and said conically shaped body having its inner and outer faces provided with lugs.

EPHRAIM E. JONES. 

